Check out this video from Collin's Lab: http://www.youtube.com/user/makemagazine#p/c/DE23FAC8A681FA46/1/GPokkuX_jjk

It talks about some of the hardware you can use, and also the basics of multiplexing. Now, I don't know if with this you can control LEDs with PWM signal or with just ON/OFF signals, but it's worth a try.

The suggested hardware is kinda expensive, but, fortunately, the manufacturer (Maxim), gives away samples on their website. If after watching the video you want to try this out, you can order the hardware, free of charge, from Maxim's website.

I was looking at those Maxim drivers but didn't think any of them supported PWM. Am I wrong?

Nice to know about the free samples!

Like I said, I'm not sure if they can run PWM signal, I have a couple but haven't used them (too busy burning Macbook's logic boards :S ). But in case you try it, post back with the results. I'm planning on using them on a future project, and would be nice if I could get PWM control.

Something else I remembered: you can try using an LED painter from Brillidea (http://www.brilldea.com/product_LEDPainter.html). It might be overkill, or it might be what you're looking for

He is using the SPI port to send data to four 8-bit shift registers: Rows, Red, Green, Blue. He sets the color bits LOW and the Row bit HIGH to turn on LEDs in a specific row. The SPI Slave Select line goes to the Latch input of the serial-in, parallel out shift registers. When the Slave Select line goes HIGH the bits that were shifted into the shift register appear on the outputs.

The circuit diagram is shown here:http://francisshanahan.com/index.php/2009/how-to-build-a-8x8x3-led-matrix-with-pwm-using-an-arduino/

And if you're thinking about using that piece of code, please make sure you get the latest version. The one that was linked above is pretty old and a bit sub-optimal.

Also if you're interested in getting a decent level of brightness (good visibility in broad daylight), you'll definitely want a bit more than plain 595 chips, probably even dedicated constant current drivers. Saves you from using tons of resistors.

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